This invention relates generally to modular large area displays.
Large area displays use a number of modules which are connected together. Each of the modules produces a portion of an overall image which is discernible from the composite of modules. Large area displays made in a modular format have advantages since the probability of forming defects is a function of how large is the device being made. Thus, the yield may be higher with devices made in smaller sizes and then assembled into a larger structure.
Each pixel includes a light altering member which produces light of a particular color. Commonly, a single pixel will include light altering elements for each color in a tri-color color space such as red, green and blue.
In emissive displays, such as organic light emitting device (OLED) displays, each subpixel associated with a particular color is sandwiched between row and column electrodes. In one example, the row, column and OLED material may be deposited on a transparent panel such as a glass panel. The OLED material may produce light when an appropriate potential is applied across it by way of the row and column electrodes. Conventionally, the column electrodes are made light transmissive using indium tin oxide, for example. Thus, light output from the emitting material passes through the column electrodes and out through the glass panel.
The glass panel and its associated electrodes and OLED material may be referred to as a display panel. The display panel may be attached to a circuit board which conditions signals for the display panel. Thus, an electrical connection is needed between the display panel and the circuit board. This connection may be made using solder balls and surface mount connections between the display panel and the circuit board.
Traditionally, such connections are made around the periphery of the overall display. However, this has many disadvantages including the fact that the available edge space may be limited in some cases. In addition, the edge regions may be subject to disruption from impact or the use of sealing materials to interface one module with adjacent modules.
Thus, there is a need for better ways to interconnect the display panel with the circuit board in a course of making large area displays.